While cleaning the inside of my amp tonight, I noticed that ......whatever it is, the wire is broken on it. It looks like a small cylinder that has two wires that are in an insulated tubes and the cylinder....the size of an eraser head, snaps into a clip on the base plate. There is another cylinder like this on the other side of the amp as well. What is it and where do I get a replacement for it? Appreciate your help.